I think iBeacon is a particular UUID ('belonging' to Apple because it is generated from their domain name?). It IS just an advertisement, that is, no connection is made, but the advertisement does carry some extra data. I think you could make a generic beacon (Apple doesn't own the idea of beacons) by just advertising some arbitrary UUID (not necessarily associated with any service, since it is connectionless.) The question is, can you make your other device (hearing the beacon) treat that advertisement as a beacon. I could be wrong, I am new to the Curie and to BLE.
I am interested in a cluster of Curies, all beacons but also listening for beacons. Its not clear to me that the CurieBLE library supports that. That is, the heart rate example seems to show the Curie/Arduino101 as a peripheral, and some other device as a central (or client of the peripheral, treating the peripheral as a server.) The example doesn't show the Curie as a client of another peripheral.
I think one answer was suggesting that you might need to modify both the CurieBLE library AND the firmware in the Curie (which was recently released, seems to run on one of the processor in the Curie, and handles BLE.) In other words, there is a very limited API between sketches and the firmware on the Curie. Because it is all new and evolving. I could be wrong.